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Basic Plots

Mental Model for Plots

Think of plots as nested structures:

PGFPlot (tikzpicture wrapper)
└── Axis (the coordinate system)
    ├── Options (xlabel, ylabel, limits, grid, ...)
    ├── Plots (list of AddPlot)
    │   └── AddPlot
    │       ├── Style (color, mark, line style)
    │       └── Data (Coordinates or expression)
    └── Legend
  • PGFPlot: The tikzpicture wrapper
  • Axis: The coordinate system with labels and limits
  • AddPlot: A single plot/series
  • Coordinates: Data points or mathematical expression

Your First Plot

Let's create a simple scatter plot with static data:

from texer import PGFPlot, Axis, AddPlot, Coordinates, evaluate

plot = PGFPlot(
    Axis(
        xlabel="Time (s)",
        ylabel="Distance (m)",
        plots=[
            AddPlot(
                color="blue",
                mark="*",
                coords=Coordinates([(0, 0), (1, 2), (2, 8), (3, 18)]),
            )
        ],
    )
)

print(evaluate(plot, {}))
LaTeX code 
\begin{tikzpicture}
  \begin{axis}[xlabel={Time (s)}, ylabel={Distance (m)}]
    \addplot[color=blue, mark=*] coordinates {(0, 0) (1, 2) (2, 8) (3, 18)};
  \end{axis}
\end{tikzpicture}

Understanding the Parts

Axis Options

Axis(
    # Labels
    xlabel="X Axis",
    ylabel="Y Axis",
    title="Plot Title",

    # Limits
    xmin=0, xmax=10,
    ymin=-5, ymax=5,

    # Grid
    grid=True,              # Show grid

    # Dimensions
    width="10cm",
    height="6cm",

    # Plots and legend
    plots=[...],
    legend=["Series 1", "Series 2"],
    legend_pos="north west",
)

AddPlot Style Options

AddPlot(
    # Color - named colors or hex codes
    color="blue",           # Named color: "red", "green", "black", etc.
    color="#5D8AA8",        # Hex color: automatically converted to RGB

    # Markers
    mark="*",              # *, o, square*, triangle*, etc.
    mark_size="2pt",

    # Lines
    style="dashed",        # solid, dashed, dotted, dashdotted
    line_width="1pt",
    thick=True,            # Shorthand for thick line

    # Mark control
    only_marks=True,       # Scatter plot (no lines)
    no_marks=True,         # Line plot (no markers)

    # Data
    coords=Coordinates(...),
)

Using Hex Colors

You can use hex color codes (with or without # prefix) for precise color control:

plot = PGFPlot(
    Axis(
        xlabel="X",
        ylabel="Y",
        plots=[
            AddPlot(
                color="#FF5733",  # Coral orange
                mark="*",
                coords=Coordinates([(0, 0), (1, 2), (2, 4)]),
            ),
            AddPlot(
                color="#1E90FF",  # Dodger blue
                mark="square*",
                coords=Coordinates([(0, 1), (1, 3), (2, 5)]),
            ),
        ],
        legend=["Series A", "Series B"],
    )
)

Hex colors are automatically converted to PGF's RGB format:

  • #5D8AA8 becomes {rgb,255:red,93; green,138; blue,168}
  • #FF0000 becomes {rgb,255:red,255; green,0; blue,0}

This works with both static values and dynamic Ref specs.

Common Marker Types

Mark Appearance
* Filled star
o Circle
square* Filled square
triangle* Filled triangle
diamond* Filled diamond
+ Plus sign
x Cross

Plot Types

Scatter Plot

plot = PGFPlot(
    Axis(
        xlabel="X",
        ylabel="Y",
        plots=[
            AddPlot(
                color="red",
                mark="o",
                only_marks=True,  # No connecting lines
                coords=Coordinates([(1, 2), (2, 4), (3, 3), (4, 5)]),
            )
        ],
    )
)

Line Plot

plot = PGFPlot(
    Axis(
        xlabel="Time",
        ylabel="Value",
        plots=[
            AddPlot(
                color="blue",
                thick=True,
                no_marks=True,  # No markers, just line
                coords=Coordinates([(0, 1), (1, 2), (2, 4), (3, 8)]),
            )
        ],
    )
)

Line + Markers

plot = PGFPlot(
    Axis(
        plots=[
            AddPlot(
                color="green",
                mark="square*",
                coords=Coordinates([(0, 0), (1, 1), (2, 4), (3, 9)]),
            )
        ],
    )
)

Using NumPy Arrays

You can pass NumPy arrays directly:

import numpy as np
from texer import PGFPlot, Axis, AddPlot, Coordinates, evaluate

# Generate data
x = np.linspace(0, 2*np.pi, 100)
y = np.sin(x)

plot = PGFPlot(
    Axis(
        xlabel="$x$",
        ylabel="$\\sin(x)$",
        grid=True,
        plots=[
            AddPlot(
                color="blue",
                thick=True,
                no_marks=True,
                coords=Coordinates(x=x, y=y),  # Direct from NumPy!
            )
        ],
    )
)

print(evaluate(plot, {}))

Grid and Styling

plot = PGFPlot(
    Axis(
        xlabel="Time (s)",
        ylabel="Voltage (V)",
        title="Sensor Readings",
        grid=True,               # Show grid
        width="12cm",
        height="8cm",
        xmin=0, xmax=10,
        ymin=0, ymax=5,
        plots=[...],
    )
)

Multiple Series

Add multiple AddPlot instances with a legend:

plot = PGFPlot(
    Axis(
        xlabel="X",
        ylabel="Y",
        grid=True,
        plots=[
            AddPlot(
                color="blue",
                mark="*",
                coords=Coordinates([(0, 0), (1, 1), (2, 4)]),
            ),
            AddPlot(
                color="red",
                mark="square*",
                style="dashed",
                coords=Coordinates([(0, 1), (1, 2), (2, 3)]),
            ),
        ],
        legend=["Series A", "Series B"],
        legend_pos="north west",
    )
)

Legend Positions

Position Location
north west Top left
north east Top right
south west Bottom left
south east Bottom right
outer north east Outside plot area, right side

Mathematical Expressions

Plot mathematical functions directly:

plot = PGFPlot(
    Axis(
        xlabel="$x$",
        ylabel="$f(x)$",
        xmin=-5, xmax=5,
        ymin=-1.5, ymax=1.5,
        grid=True,
        plots=[
            AddPlot(
                expression="sin(deg(x))",
                domain="-5:5",
                samples=100,
                color="blue",
                thick=True,
                no_marks=True,
            ),
        ],
    )
)

Trigonometric Functions

PGFPlots expects angles in degrees. Use deg(x) to convert radians to degrees.

Next Steps